Posterior lumbar interbody fusion (PLIF) and transforaminal lumbar interbody fusion (TLIF) are common modes of operative treatment of lumbar radiculopathy and spondylolisthesis. An integral part of these procedures is the appropriate placement of pedicle screws to ensure proper fusion. Breach of the medial cortex during pedicle screw fixation can potentially cause permanent impairment for a patient; significant technology and resources have been universally devoted to preventing this complication. Intraoperative neuromonitoring (IONM) is a frequently used tool by spine surgeons, which, along with fluoroscopy, is traditionally thought to reduce the incidence of neurologic injury. Unfortunately, IONM is not infallible and, in certain studies, has not been shown to decrease the risk of neurologic compromise. This case presentation details the clinical course of a 55-year-old who underwent an L4-5 TLIF. Despite benign electromyography recordings intraoperatively, the patient presented postoperatively with a new-onset left foot drop and a CT scan that confirmed bilateral L4 screw malposition with a breach of the medial cortex. We hope to further advance the discussion regarding the dangerous inconsistency of IONM in hopes of identifying a multimodal approach to avoid dreaded complications like this one in the future.